Condenser



F. GERTH CQNDENSER oen 29, 1940.

Filed Oct. 4, 1935 Patented Oct. 29, 1940 i IIJNITED STATES PATENT OFFICE CONDENSER Felix Gerth, Berlin-Tempelhof, Germany, assignor to C. Lorenz Aktiengesellschaft, Berlin- Tempelhof, Germany, a company l Application October 4, 1935, Serial No. 43,480 In Germany October 6, 1934 1 Claim. (Cl. F75-41.5)

Ceramic materials have recently become known these excavations 8 of the plates I, 2, and the which owing to their small phase-or angleedges of these excavations are turned inward in difference and their high dielectric constant are the manner appearing from Fig. 2, so as to form Vparticularly well adapted for use with condensers a sort of torus 9 at the edge of each coating 5 5 as the dielectric thereof. Such materials, howand 6. These toruses act to avoid glow disever, in order to prove satisfactory require the charges and corona discharges as well as the condensers to be given special forms. ln parwell known sparking over, and above all do away ticular, if the customary condensers are in a with any breakdown phenomena. The electric simple manner tted with intermediate layers strength thus created is active at any point of of ceramic material, the requisite high breakthe edge of the coatings since these are com- 10 down voltages are dimcult to obtain, because in pletely encircled by the toruses S. this case a rigid material and air constitute the Condensers having ceramic plates adapted to dielectric. be turned in relation to one another are known Therefore by the invention a construction of perse but are of simple construction, being incondensers is proposed which is adapted to obtended for relatively small potentials such as 5 viate the formation of air cavities and thus those dealt with in broadcast receivers. The avoids breakdown phenomena. A variable conobject in the case of these known condensers is denser according to the' invention has ceramic not to adapt themfor great voltages, and none of plates which are ground onto each other and them have plates ground onto each other or are at their outer surfaces provided with the torus-shaped edge portions encircling the metal 20 metal coatings. coatings.

One embodiment of the invention is illustrated The invention is intended for use with condenin the accompanying drawing in which sers of any conguration.

Fig. 1 is an end view, Fig. 2 a sectional view of What is claimed is: 5 the condenser. A variable condenser adapted to withstand Ihis condenser has two circular plates I, 2 of high potential differences comprising two ce- 25 ceramic material, which are provided with axles ramic bodies disposed in close contact with each 3, 4 and are at their surfaces I ground onto each other, the portions of said bodies which are in other, so that as in the case of adhesion plates contact with each other being closely tted so no air cavities are between them. By means of as to substantially eliminate cavities between the axles 3, 4 the plates I, 2 can be turned with said bodies, means for rotating said bodies with respect to each other, the condenser being adrespect to one another comprising a separate justable in this way. The metal coatings 5, 6 spindle for each plate, each of said spindles terare disposed on the outer faces of the plates to minating at a point short of the contacting surcover these faces partially. They are in a manfaces of said bodies, two metallic coatings one on r ner customary with circular plate condensers each of said ceramic bodies disposed essentially 3" fixed on the plates I, 2 by melting, or are electroparallel with each ,other, the space between said deposited on a layer that in its turn is produced eeatings being Wholly filled With the Ceramic ma- On the plates I, 2 by a melting process. terial which constitutes the two bodies and said Since at `I ceramic material is grinding on a Ceramic material extending beyODd the edges 0f material likewise ceramic, the plates I, 2 are not; said coatings so that the shortest electrostatic 40 likely to wear away when turned with respect to path between said coatings which extends Wholly each other, so that air cavities are not likely to 01' Partially through air iS many times aS 10118 es be formed. the shortest path which extends through the The metal coatings 5, 6 are contained in ex- Ceramic materiel.

cavations t of the plates I, 2 and the edges of FELIX GER'TR 45 

